Revert "Add full support for line continuation in the preprocessor"

Warning in the Linux/Mac builders:

In file included from ../../third_party/angle/src/tests/preprocessor_tests/input_test.cpp:7:
In file included from ../../third_party/angle/src/tests/preprocessor_tests/PreprocessorTest.h:7:
../../testing/gtest/include/gtest/gtest.h:1392:16: error: comparison of integers of different signs: 'const int' and 'const unsigned long' [-Werror,-Wsign-compare]
  if (expected == actual) {
      ~~~~~~~~ ^  ~~~~~~
../../testing/gtest/include/gtest/gtest.h:1422:12: note: in instantiation of function template specialization 'testing::internal::CmpHelperEQ<int, unsigned long>' requested here
    return CmpHelperEQ(expected_expression, actual_expression, expected,
           ^
../../third_party/angle/src/tests/preprocessor_tests/input_test.cpp:171:5: note: in instantiation of function template specialization 'testing::internal::EqHelper<false>::Compare<int, unsigned long>' requested here
    EXPECT_EQ(3, input.read(buf, maxSize, &lineNo));
    ^

BUG=angleproject:1125

This reverts commit c1157d1963170c7411eb6c32e2b2fbce02c5a170.

Change-Id: Ic6fa286d190b006cccc5154d86e21ecc03175763
Reviewed-on: https://chromium-review.googlesource.com/294080
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/compiler/preprocessor/Tokenizer.cpp b/src/compiler/preprocessor/Tokenizer.cpp
index eb6156f..75df434 100644
--- a/src/compiler/preprocessor/Tokenizer.cpp
+++ b/src/compiler/preprocessor/Tokenizer.cpp
@@ -594,7 +594,7 @@
     } while(0);
 
 #define YY_INPUT(buf, result, maxSize) \
-    result = yyextra->input.read(buf, maxSize, &yylineno);
+    result = yyextra->input.read(buf, maxSize);
 
 #define INITIAL 0
 #define COMMENT 1