Rename EmitArgs::fSamplers to fTexSamplers

Renames fSamplers to fTexSamplers in GrProcessor EmitArgs, and renames
GrGLSLTextureSampler to GrGLSLSampler. This will allow us to add a
second array of buffer samplers.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1862373003

Review URL: https://codereview.chromium.org/1862373003
diff --git a/src/effects/SkTableColorFilter.cpp b/src/effects/SkTableColorFilter.cpp
index 10b71f8..0994097 100644
--- a/src/effects/SkTableColorFilter.cpp
+++ b/src/effects/SkTableColorFilter.cpp
@@ -437,22 +437,22 @@
 
     fragBuilder->codeAppendf("\t\t%s.a = ", args.fOutputColor);
     coord.printf("vec2(coord.a, %s.a)", yoffsets);
-    fragBuilder->appendTextureLookup(args.fSamplers[0], coord.c_str());
+    fragBuilder->appendTextureLookup(args.fTexSamplers[0], coord.c_str());
     fragBuilder->codeAppend(".a;\n");
 
     fragBuilder->codeAppendf("\t\t%s.r = ", args.fOutputColor);
     coord.printf("vec2(coord.r, %s.r)", yoffsets);
-    fragBuilder->appendTextureLookup(args.fSamplers[0], coord.c_str());
+    fragBuilder->appendTextureLookup(args.fTexSamplers[0], coord.c_str());
     fragBuilder->codeAppend(".a;\n");
 
     fragBuilder->codeAppendf("\t\t%s.g = ", args.fOutputColor);
     coord.printf("vec2(coord.g, %s.g)", yoffsets);
-    fragBuilder->appendTextureLookup(args.fSamplers[0], coord.c_str());
+    fragBuilder->appendTextureLookup(args.fTexSamplers[0], coord.c_str());
     fragBuilder->codeAppend(".a;\n");
 
     fragBuilder->codeAppendf("\t\t%s.b = ", args.fOutputColor);
     coord.printf("vec2(coord.b, %s.b)", yoffsets);
-    fragBuilder->appendTextureLookup(args.fSamplers[0], coord.c_str());
+    fragBuilder->appendTextureLookup(args.fTexSamplers[0], coord.c_str());
     fragBuilder->codeAppend(".a;\n");
 
     fragBuilder->codeAppendf("\t\t%s.rgb *= %s.a;\n", args.fOutputColor, args.fOutputColor);