tests/functional/lang: update error path locations

The coerce integer feature was not rebased before merge and we do not
have a merge queue, hence, after merge, the HEAD was in a broken state.

We take a commitment to invest into a merge queue now and do a fixup
here.

Change-Id: Ied9410690b542359859ab5f597f22ebceb857305
Signed-off-by: Raito Bezarius <raito@lix.systems>

tests/functional/lang/eval-fail-accidental-coerce-integer-attempts.err.exp

@@ -1,12 +1,12 @@
 error:
        … while evaluating x
-         at /pwd/lang/eval-fail-accidental-coerce-integer-attempts.nix:1:21:
+         at /pwd/eval-fail-accidental-coerce-integer-attempts.nix:1:21:
             1| let x = "" + 42; in x == "42"
              |                     ^
             2|
 
        … while evaluating a path segment
-         at /pwd/lang/eval-fail-accidental-coerce-integer-attempts.nix:1:14:
+         at /pwd/eval-fail-accidental-coerce-integer-attempts.nix:1:14:
             1| let x = "" + 42; in x == "42"
              |              ^
             2|

tests/functional/lang/eval-fail-coerce-integers-without-xp.err.exp

@@ -1,6 +1,6 @@
 error:
        … while evaluating a path segment
-         at /pwd/lang/eval-fail-coerce-integers-without-xp.nix:1:2:
+         at /pwd/eval-fail-coerce-integers-without-xp.nix:1:2:
             1| "${42}" == 42
              |  ^
             2|

tests/functional/lang/eval-fail-over-coercive-builtins-with-xp-feature.err.exp

@@ -1,6 +1,6 @@
 error:
        … while calling the 'substring' builtin
-         at /pwd/lang/eval-fail-over-coercive-builtins-with-xp-feature.nix:1:1:
+         at /pwd/eval-fail-over-coercive-builtins-with-xp-feature.nix:1:1:
             1| builtins.substring 0 1 42 == "4"
              | ^
             2|