Fix; correct placement of type inference error for method calls

[Jamesbarford]

Addresses a FIXME for displaying errors on method calls;

Before;

error[E0282]: type annotations needed
  --> /<location>/src/main.rs:48:15
   |
## |             e.is_conversion_error();
   |               ^^^^^^^^^^^^^^^^^^^ cannot infer type

After;

error[E0282]: type annotations needed
  --> /<location>/src/main.rs:48:15
   |
## |             e.is_conversion_error();
   |             ^ cannot infer type

[rustbot]

This PR modifies tests/ui/issues/. If this PR is adding new tests to tests/ui/issues/,
please refrain from doing so, and instead add it to more descriptive subdirectories.

[rustbot]

r? @davidtwco

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[chenyukang]

all the changes in tests code are pretty good, I'm not sure whether there is some other way to get the self expr's span, so many fn signature need to change for the new extra parameter.