[Dexter] Update Dexter tests to use new dexter test substitutions

Following commit b8fc288, which changed some dexter test substitutions to
be specific to C and C++, some tests that had been added since the original
patch was written were still using the old substitution; this patch updates
them to use the new.
diff --git a/cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/perfect/dex_declare_file/precompiled_binary/commands.dex b/cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/perfect/dex_declare_file/precompiled_binary/commands.dex
index 99b0a50..970106c 100644
--- a/cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/perfect/dex_declare_file/precompiled_binary/commands.dex
+++ b/cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/perfect/dex_declare_file/precompiled_binary/commands.dex
@@ -4,7 +4,7 @@
 #
 # UNSUPPORTED: system-darwin
 #
-# RUN: %dexter_regression_test_build %S/test.cpp -o %t
+# RUN: %dexter_regression_test_cxx_build %S/test.cpp -o %t
 # RUN: %dexter_regression_base --binary %t %s | FileCheck %s
 # CHECK: commands.dex
 #
diff --git a/cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/perfect/dex_declare_file/windows_noncanonical_path/test.dex b/cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/perfect/dex_declare_file/windows_noncanonical_path/test.dex
index ec48bc3..b96562e 100644
--- a/cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/perfect/dex_declare_file/windows_noncanonical_path/test.dex
+++ b/cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/perfect/dex_declare_file/windows_noncanonical_path/test.dex
@@ -3,7 +3,7 @@
 #
 # REQUIRES: system-windows
 #
-# RUN: %dexter_regression_test_build "%S/source/test file.cpp" -o %t
+# RUN: %dexter_regression_test_cxx_build "%S/source/test file.cpp" -o %t
 # RUN: %dexter_regression_base --binary %t %s | FileCheck %s
 # CHECK: test.dex
 #
diff --git a/cross-project-tests/debuginfo-tests/dexter/feature_tests/subtools/test/err_syntax_dexdeclarefile.cpp b/cross-project-tests/debuginfo-tests/dexter/feature_tests/subtools/test/err_syntax_dexdeclarefile.cpp
index e3f08af..40cc158 100644
--- a/cross-project-tests/debuginfo-tests/dexter/feature_tests/subtools/test/err_syntax_dexdeclarefile.cpp
+++ b/cross-project-tests/debuginfo-tests/dexter/feature_tests/subtools/test/err_syntax_dexdeclarefile.cpp
@@ -2,7 +2,7 @@
 //      Check that Dexter command syntax errors associate with the line and file
 //      they appeared in rather than the current declared file.
 //
-// RUN: %dexter_regression_test_build %s -o %t
+// RUN: %dexter_regression_test_cxx_build %s -o %t
 // RUN: not %dexter_base test --binary %t --debugger 'lldb' -v -- %s \
 // RUN:     | FileCheck %s --implicit-check-not=FAIL-FILENAME-MATCH