Run GrTextureMipMapInvalidationTest on rendering contexts

The logic being tested is implemented in the various Gr*Gpu classes, so
running it on the NullGL context seems like an oversight.

Bug: skia:
Change-Id: I629010f0abde9347f06602a6b8774df7a19a3da7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/203704
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>

tests/GrTextureMipMapInvalidationTest.cpp

@@ -14,7 +14,12 @@
 #include "Test.h"
 
 // Tests that MIP maps are created and invalidated as expected when drawing to and from GrTextures.
-DEF_GPUTEST_FOR_NULLGL_CONTEXT(GrTextureMipMapInvalidationTest, reporter, ctxInfo) {
+DEF_GPUTEST_FOR_RENDERING_CONTEXTS(GrTextureMipMapInvalidationTest, reporter, ctxInfo) {
+    GrContext* context = ctxInfo.grContext();
+    if (!context->priv().caps()->mipMapSupport()) {
+        return;
+    }
+
     auto isMipped = [] (SkSurface* surf) {
         const GrTexture* texture = surf->makeImageSnapshot()->getTexture();
         return GrMipMapped::kYes == texture->texturePriv().mipMapped();
@@ -24,7 +29,6 @@ DEF_GPUTEST_FOR_NULLGL_CONTEXT(GrTextureMipMapInvalidationTest, reporter, ctxInf
         return surf->makeImageSnapshot()->getTexture()->texturePriv().mipMapsAreDirty();
     };
 
-    GrContext* context = ctxInfo.grContext();
     auto info = SkImageInfo::MakeN32Premul(256, 256);
     for (auto allocateMips : {false, true}) {
         auto surf1 = SkSurface::MakeRenderTarget(context, SkBudgeted::kYes, info, 0,