Recommit: Compress formatting of array type names (int [4] -> int[4])

Based on post-commit review discussion on
2bd84938470bf2e337801faafb8a67710f46429d with Richard Smith.

Other uses of forcing HasEmptyPlaceHolder to false seem OK to me -
they're all around pointer/reference types where the pointer/reference
token will appear at the rightmost side of the left side of the type
name, so they make nested types (eg: the "int" in "int *") behave as
though there is a non-empty placeholder (because the "*" is essentially
the placeholder as far as the "int" is concerned).

This was originally committed in 277623f4d5a672d707390e2c3eaf30a9eb4b075c

Reverted in f9ad1d1c775a8e264bebc15d75e0c6e5c20eefc7 due to breakages
outside of clang - lldb seems to have some strange/strong dependence on
"char [N]" versus "char[N]" when printing strings (not due to that name
appearing in DWARF, but probably due to using clang to stringify type
names) that'll need to be addressed, plus a few other odds and ends in
other subprojects (clang-tools-extra, compiler-rt, etc).
diff --git a/clang/test/SemaCXX/for-range-examples.cpp b/clang/test/SemaCXX/for-range-examples.cpp
index 5424b7a..5376f48 100644
--- a/clang/test/SemaCXX/for-range-examples.cpp
+++ b/clang/test/SemaCXX/for-range-examples.cpp
@@ -196,7 +196,7 @@
 namespace test6 {
   void foo(int arr[]) {  // expected-note {{declared here}}
     for (auto i : arr) { }
-      // expected-error@-1 {{cannot build range expression with array function parameter 'arr' since parameter with array type 'int []' is treated as pointer type 'int *'}}
+      // expected-error@-1 {{cannot build range expression with array function parameter 'arr' since parameter with array type 'int[]' is treated as pointer type 'int *'}}
   }
 
   struct vector {
@@ -207,7 +207,7 @@
   void foo(vector arr[]) {  // expected-note {{declared here}}
     // Don't suggest to dereference arr.
     for (auto i : arr) { }
-      // expected-error@-1 {{cannot build range expression with array function parameter 'arr' since parameter with array type 'test6::vector []' is treated as pointer type 'test6::vector *'}}
+      // expected-error@-1 {{cannot build range expression with array function parameter 'arr' since parameter with array type 'test6::vector[]' is treated as pointer type 'test6::vector *'}}
   }
 }