Add missing last line in Exception trace capture

[yann-eugone]

Throwable::getTraceAsString method do not include the line where the exception is thrown.
This PR is adding this information to the captured stacktrace when converting Exceptions to Failures.

Now, traces will be something like

Exception: Thrown from class C (at /in/uVj23(43))
#0 /in/uVj23(35): C->exc()
#1 /in/uVj23(50): C->doexc()
#2 /in/uVj23(54): fail2()
#3 /in/uVj23(58): fail1()
#4 {main}
Caused by: Exception: Thrown from class B (at /in/uVj23(29))
#0 /in/uVj23(40): B->exc()
#1 /in/uVj23(35): C->exc()
#2 /in/uVj23(50): C->doexc()
#3 /in/uVj23(54): fail2()
#4 /in/uVj23(58): fail1()
#5 {main}

[codecov]

Codecov Report

Merging #58 (94c1ac8) into 0.x (ee11d80) will not change coverage.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##                 0.x       #58   +/-   ##
===========================================
  Coverage     100.00%   100.00%           
- Complexity       714       717    +3     
===========================================
  Files            121       121           
  Lines           1820      1827    +7     
===========================================
+ Hits            1820      1827    +7     

Impacted Files	Coverage Δ
src/batch/src/Failure.php	100.00% <100.00%> (ø)

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