Increase the space used by properties filenames

The filename size for properties has 74 bytes overhead when used by
CtsBionicTestCases testcases as they have this form:

/data/local/tmp/TemporaryDir-fntJb8/appcompat_override/u:object_r:PROPERTY_NAME_prop:s0

With this overhead, a 128-byte filename size leaves only 53 bytes for
property names. Longer names cause abort() in several test cases, e.g.
__system_property_update(), resulting in CTS failures on some devices.

Bring the size up to 256 bytes.

Bug: 357631695
Test: run cts-dev -m CtsBionicTestCases -t properties#*
Fixes: I524d7e5ffd415ba0c3d600eb94801a304b1b4bb4
Change-Id: Ic93c2ea28eed2f5f392cc8fe366ed10eb6dcac6b

Author: JustGalaxy30

libc/system_properties/include/system_properties/properties_filename.h

@@ -46,6 +46,8 @@ class PropertiesFilename {
   const char* c_str() { return filename_; }
 
  private:
-  // Typically something like "/dev/__properties__/properties_serial".
-  char filename_[128];
+  // Typically something like "/dev/__properties__/properties_serial", but can be as long as
+  // "/data/local/tmp/TemporaryDir-fntJb8/appcompat_override/u:object_r:PROPERTY_NAME_prop:s0"
+  // when running CTS.
+  char filename_[256];
 };