Auto merge of #13478 - mmatyas:arm_gles3, r=jdm

Use GL ES3 on ARM devices

<!-- Please describe your changes on the following line: -->
This makes WebRender work on ARM devices; see servo/webrender#408.

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `PKG_CONFIG_ALLOW_CROSS=1 PKG_CONFIG_PATH=/usr/lib/arm-linux-gnueabihf/pkgconfig HARFBUZZ_NO_PKG_CONFIG=1 EXPAT_NO_PKG_CONFIG=1 FREETYPE2_NO_PKG_CONFIG=1 FONTCONFIG_NO_PKG_CONFIG=1 CC=arm-linux-gnueabihf-gcc CXX=arm-linux-gnueabihf-g++ ./mach build --dev --target=arm-unknown-linux-gnueabihf` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #10310.

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ports/glutin/window.rs

@@ -317,7 +317,7 @@ impl Window {
         }
     }
 
-    #[cfg(not(target_os = "android"))]
+    #[cfg(not(any(target_arch = "arm", target_arch = "aarch64")))]
     fn gl_version() -> GlRequest {
         if opts::get().use_webrender {
             return GlRequest::Specific(Api::OpenGl, (3, 2));
@@ -332,7 +332,7 @@ impl Window {
         }
     }
 
-    #[cfg(target_os = "android")]
+    #[cfg(any(target_arch = "arm", target_arch = "aarch64"))]
     fn gl_version() -> GlRequest {
         GlRequest::Specific(Api::OpenGlEs, (3, 0))
     }