Made it so angle builds on linux (#56328)

fixes: flutter/flutter#151353

Before this PR, angle would not build on linux, now it does.

example:
```
./flutter/bin/et build -c host_debug_unopt //flutter/third_party/angle:libGLESv2
```

There isn't a CI step that builds this today to verify it keeps working, I implemented this as part of the work to see if i could get the golden test runner working on linux.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

Author: gaaclarke

build_overrides/angle.gni

@@ -31,8 +31,7 @@ angle_spirv_headers_dir = "//flutter/third_party/vulkan-deps/spirv-headers/src"
 angle_spirv_tools_dir = "//flutter/third_party/vulkan-deps/spirv-tools/src"
 angle_spirv_cross_dir = "//flutter/third_party/vulkan-deps/spirv-cross/src"
 angle_spirv_headers_dir = "//flutter/third_party/vulkan-deps/spirv-headers/src"
-angle_vulkan_memory_allocator_dir =
-    "//flutter/third_party/vulkan_memory_allocator"
+angle_vulkan_memory_allocator_dir = "//flutter/flutter_vma"
 
 # This is a general Chromium flag, but in the Flutter build only ANGLE needs it
 # so it is defined here.

ci/licenses_golden/excluded_files

@@ -84,6 +84,7 @@
 ../../../flutter/flow/texture_unittests.cc
 ../../../flutter/flow/view_slicer_unittests.cc
 ../../../flutter/flutter_frontend_server
+../../../flutter/flutter_vma/include/README.md
 ../../../flutter/fml/ascii_trie_unittests.cc
 ../../../flutter/fml/backtrace_unittests.cc
 ../../../flutter/fml/base32_unittest.cc

flutter_vma/include/README.md

@@ -0,0 +1 @@
+This folder is here to match Angle's expectations for the VMA directory.