Revert "Fixed DSL assertion error on source files containing nulls"

This reverts commit db38ad7b14.

Reason for revert: breaking g3 roll since it thinks the test case is "binary" not flagged as binary

Original change's description:
> Fixed DSL assertion error on source files containing nulls
>
> The assertion was there to make sure we weren't running off the end of
> the source, but naturally fails in the presence of legitimate embedded
> nulls.
>
> Change-Id: I3b80499e9b182c9ea046c479f35d7a965d548401
> Bug: oss-fuzz:38107
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/447182
> Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
> Reviewed-by: John Stiles <johnstiles@google.com>
> Reviewed-by: Brian Osman <brianosman@google.com>

Bug: oss-fuzz:38107
Change-Id: I650d12d728b5d932bda79e81205b873d8b44771f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/447936
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>

gn/sksl_tests.gni

@@ -101,7 +101,6 @@ sksl_error_tests = [
   "/sksl/errors/Ossfuzz37465.sksl",
   "/sksl/errors/Ossfuzz37620.sksl",
   "/sksl/errors/Ossfuzz38106.sksl",
-  "/sksl/errors/Ossfuzz38107.sksl",
   "/sksl/errors/Ossfuzz38140.sksl",
   "/sksl/errors/OverflowFloatLiteral.sksl",
   "/sksl/errors/OverflowIntLiteral.sksl",

include/sksl/SkSLErrorReporter.h

@@ -53,6 +53,7 @@ public:
             }
             fLine = 1;
             for (int i = 0; i < fOffset; i++) {
+                SkASSERT(fText[i]);
                 if (fText[i] == '\n') {
                     ++fLine;
                 }

tests/sksl/errors/Ossfuzz38107.glsl

@@ -1,4 +0,0 @@
-### Compilation failed:
-
-error: 1: invalid token
-1 error